The present invention relates to a conveyor system for sorting articles, such as luggage, to a plurality of receiving means, in which cross-over means are arranged for shifting articles from a first conveyor, along which at least two induction stations and at least two discharge stations each comprising a plurality of receiving means are arranged alternately, and to a second conveyor so as to short-cut the conveying path of articles that have been loaded onto the first conveyor at a first induction station and having the second discharge station as destination. Thereby, the conveying capacity of the first conveyor occupied by said articles is released as the articles do not pass the at least one remaining induction station at which articles may be loaded onto the de-occupied parts of first conveyor and the sorting capacity of the conveyor system is increased.
In particular, the present invention relates to a system comprising two parallel conveyors and cross-over means for shifting articles between the two conveyors arranged so that the two conveyors function as short-cuts for each other.
Conveyor systems for sorting articles to a plurality of destinations are known from e.g. luggage handling systems of airport, at which luggage may be sorted by one main conveyor to 50-150 destinations or even more and each destination has a receiving means arranged along the conveying path of the conveyor assigned to it. Induction stations and discharge stations comprising each a plurality of receiving means may be arranged in various formations along the conveying path of the main conveyor, such as induction stations alternating with discharge station.
It is a problem for the sorting capacity of such a main sorter that articles may have to travel along most of the conveying path from they are loaded onto the conveyor and until they are discharged into a receiving means and thus occupying a part of the main conveyor for a long period and it is an object of the present invention to increase the conveying and sorting capacity of a conveyor system by shortening the occupation time for at least some of the articles.
This problem is solved by the present invention by means of arranging short-cuts by means of shifting means/cross-over means and a second conveyor for articles assigned to destinations of which the assigned receiving means are situated far away along the conveying path from the induction station at which said articles are loaded onto the main conveyor and thus releasing conveying capacity of the main conveyor so that said released capacity may be used by articles loaded onto the main conveyor at induction stations arranged along the conveying path in between the cross-over means and said receiving means to which the articles being shifted are assigned.
In a preferred embodiment of the present invention the conveyor system comprises two parallel conveyors and cross-over means for shifting articles between the two conveyors arranged so that the two conveyors function as short-cuts for each other. The system comprises two discharge stations each having a plurality of receiving means into which both conveyors may discharge articles and two induction stations for each conveyor, one arranged between the first and the second discharge station and one arranged between the second and the first discharge station.
Thus, the present invention relates to a method of operating a conveyor system comprising
a first conveyor for conveying articles along a first conveying path defined by first stationary track means forming a closed loop on which track means the first conveyor moves,
first discharge means for discharging articles from the first conveyor,
first drive means for driving the first conveyor in a conveying direction of the first conveyor along the first conveying path,
a first induction station arranged at a position along the first conveying path and comprising at least one loading means for loading articles onto the first conveyor,
a second induction station arranged at a position along the first conveying path and comprising at least one loading means for loading articles onto the first conveyor,
a first discharge station arranged at a position along the first conveying path in between the first induction station and the second induction station in the conveying direction of the first conveyor and comprising at least one receiving means for receiving articles being discharged from the first conveyor,
a second discharge station arranged at a position along the first conveying path in between the second induction station and the first induction station in the conveying direction of the first conveyor and comprising at least one receiving means for receiving articles being discharged from the first conveyor,
a second conveyor for conveying articles along a second conveying path defined by second stationary track means on which the second conveyor moves, the second conveying path passing at least one of the at least one receiving means of the second discharge station and said receiving means being arranged for receiving articles being discharged from the second conveyor,
second discharge means for discharging articles from the second conveyor,
second drive means for driving the second conveyor in a conveying direction of the second conveyor along the second conveying path,
first cross-over means arranged along the first conveying path in between the first induction station and the first discharge station in the conveying direction of the first conveyor for receiving articles being discharged from the first conveyor onto the first cross-over means and for loading said articles onto the second conveyor at a position along the second conveying path being upstream of the second discharge station in the conveying direction of the second conveyor, and
control means for controlling the operation of the conveyor system, the method comprising the steps of
(a) loading articles onto the first conveyor by means of the loading means of the first induction station, each article being assigned to one of the receiving means of the first discharge station and the second discharge station,
(b) discharging from the first conveyor at least some of the articles being assigned to a receiving means of the second discharge station that is arranged for receiving articles being discharged from the second conveyor onto the first cross-over means,
(c) loading articles from the first cross-over means onto the second conveyor,
(d) discharging articles from the second conveyor into the receiving means of the second discharge station to which the individual article is assigned,
(e) discharging articles from the first conveyor into the receiving means of the first discharge station to which the individual article is assigned,
(f) loading articles onto the first conveyor by means of the loading means of the second induction station, each article being assigned to one of the receiving means of the first discharge station and the second discharge station, and optionally
(g) discharging articles from the first conveyor into the receiving means of the second discharge station to which the individual article is assigned.
The first conveyor and/or the second conveyor may be a sorter having a plurality of article supporting members each defining an article supporting surface and each having means for discharging articles being supported by the article supporting surface. The sorter may be a tilt-tray sorter so that the article supporting members are trays arranged pivotally each about an axis being substantially aligned with the conveying direction of said conveyor at the position of the tray, and wherein the discharging means can cause the tray to tilt from an article supporting position to an article discharging position in which the article supporting surface is inclined so as to discharge an article supported thereon and which means can cause the tray to be restored from the discharging position to the supporting position. Alternatively, the sorter may be a cross-belt sorter wherein the article supporting members each comprises an endless belt arranged movably in a direction substantially transversal to the conveying direction of said conveyor so that an upper surface of the belt constitutes the article supporting surface, wherein the discharging means comprises drive means for driving said movement of the belt so as to discharge an article supported thereon. As another alternative, the conveyors may be belt conveyors or the like and the articles may be placed in movable containers such as trays or totes that are conveyed by the conveyors.
The driving means may be drive chains driven by electric motors, linear motors etc.
Preferably, the second stationary track means forms a closed loop and the second conveying path passes at least one of the at least one receiving means of the first discharge station in between the second discharge station and the first cross-over means in the conveying direction of the second conveyor, said receiving means being arranged for receiving articles being discharged from the second conveyor, in which case the method further comprises the optional steps of
(b1) discharging from the first conveyor at least some of the articles being assigned to a receiving means of the first discharge station that is arranged for receiving articles being discharged from the second conveyor onto the first cross-over means, and
(d1) discharging articles from the second conveyor into the receiving means of the first discharge station to which the individual article is assigned.
The advantage of this configuration is that one of two articles assigned for the same receiving means of the first discharge station and placed on article supporting members of the first conveyor being too close to each other for both to be discharged at the first passage of the receiving means may be shifted to the second conveyor by means for the first cross-over means. Furthermore, the selection of articles to be shifted from the first conveyor to the second conveyor by means of the first cross-over means does not have to be completely free of errors.
According to a more preferred embodiment of the present invention, the conveyor system further comprises
second cross-over means arranged along the first conveying path in between the second induction station and the second discharge station in the conveying direction of the first conveyor for receiving articles being discharged from the first conveyor onto the second cross-over means and for loading said articles onto the second conveyor at a position along the second conveying path in between the second discharge station and the first discharge station in the conveying direction of the second conveyor, and the method further comprises the steps of
(f1) discharging from the first conveyor at least some of the articles being assigned to a receiving means of the first discharge station that is arranged for receiving articles being discharged from the second conveyor onto the second cross-over means, and
(f2) loading articles from the second cross-over means onto the second conveyor.
Thereby, the second conveyor may also be used as a short-cut for articles being loaded onto the first conveyor at the second induction station and being assigned to receiving means of the first discharge station.
It is furthermore an advantage if the conveyor system further comprises
a third induction station arranged at a position along the second conveying path and comprising at least one loading means for loading articles onto the second conveyor, in which case the method further comprises the step of
(h) loading articles onto the first conveyor by means of the loading means of the first 35 induction station, each article being assigned to one of the receiving means of the first discharge station and the second discharge station. The conveyor system becomes much more flexible in this configuration and the conveying capacity of the second conveyor may be utilised to a higher degree.
In a most preferred embodiment which is both highly flexible and in which the conveying and sorting capacity of the conveyor system is utilised very efficiently, the conveyor system further comprises
third cross-over means arranged along the second conveying path in between the first discharge station and the second discharge station in the conveying direction of the second conveyor for receiving articles being discharged from the second conveyor onto the third cross-over means and for loading said articles onto the first conveyor at a position along the first conveying path in between the first induction station and the first discharge station in the conveying direction of the first conveyor,
a fourth induction station arranged along the second conveying path in between the second discharge station and the first discharge station in the conveying direction of the second conveyor and comprising at least one loading means for loading articles onto the second conveyor,
fourth cross-over means arranged along the second conveying path in between the fourth induction station and the first discharge station in the conveying direction of the second conveyor for receiving articles being discharged from the second conveyor onto the fourth cross-over means and for loading said articles onto the first conveyor at a position along the first conveying path in between the second induction station and the second discharge station in the conveying direction of the first conveyor, wherein the third induction station is arranged along the second conveying path in between the first discharge station and the third cross-over means in the conveying direction of the second conveyor, and the method further comprises the steps of
(i) discharging from the second conveyor at least some of the articles being assigned to a receiving means of the first discharge station onto the third cross-over means,
(j) loading articles from the third cross-over means onto the first conveyor,
(k) loading articles onto the second conveyor by means of the loading means of the fourth induction station, each article being assigned to one of the receiving means of the first discharge station and the second discharge station,
(I) discharging from the second conveyor at least some of the articles being assigned to a receiving means of the second discharge station onto the fourth cross-over means, and
(m) loading articles from the fourth cross-over means onto the first conveyor.
It is understood that more induction stations, discharge stations and cross-over means according to the present invention may be arranged along the first and/or the second conveyor and such conveyor systems may be operated according to the method of the present invention with obvious modifications.
Furthermore, the present invention relates to a conveyor system arranged as described above which may be operated according to the method of the present invention.